Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for optimizing a user equipment aggregate maximum bit rate (UE-AMBR) for dual connectivity in a wireless communication system.
Related Art
3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
Small cells using low power nodes are considered promising to cope with mobile traffic explosion, especially for hotspot deployments in indoor and outdoor scenarios. A low-power node generally means a node whose transmission power is lower than macro node and base station (BS) classes, for example pico and femto evolved NodeB (eNB) are both applicable. Small cell enhancements for evolved UMTS terrestrial radio access (E-UTRA) and evolved UMTS terrestrial radio access network (E-UTRAN) will focus on additional functionalities for enhanced performance in hotspot areas for indoor and outdoor using low power nodes.
One of potential solutions for small cell enhancement, dual connectivity has been discussed. Dual connectivity is used to refer to operation where a given user equipment (UE) consumes radio resources provided by at least two different network points connected with non-ideal backhaul. Furthermore, each eNB involved in dual connectivity for a UE may assume different roles. Those roles do not necessarily depend on the eNB's power class and can vary among UEs. Dual connectivity may be one of potential solutions for small cell enhancement.
A UE can be connected to more than one packet data network (PDN). For example, a UE may be connected to PDN 1 for Internet, and PDN 2 for voice over Internet protocol (VoIP) using IP multimedia subsystem (IMS). The UE has one unique IP address for each of its all PDN connections. Here, UE aggregate maximum bit rate (AMBR) (uplink (UL)/downlink (DL)) indicates the maximum bandwidth allowed for all the non-guaranteed bit rate (GBR) evolved packet system (EPS) bearers associated to the UE, no matter how many PDN connections the UE has. Other PDNs are connected through other PDN gateways (P-GWs), this parameter is applied by eNBs only.
A method for optimizing UE-AMBR for dual connectivity may be required.